8 ms·

Variable-length C structures don’t map. Example of such structure: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365521(v=vs.85).aspx https://msdn

Variable-length C structures don’t map. Example of such structure: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365521(v=vs.85).aspx https://msdn.microsoft.com/en-us/library/windows/desktop/aa3... But they’re rarely found in APIs, and there’s Marshal class in the framework to implement manual marshaling by reading/writing stuff at unmanaged memory addresses, even without /unsafe compiler switch.

int_19h 9y ago
With a little syntactic sugar in C#, they do map, in the same exact way you do this in C - you just use a "fixed" array of one as the last element: struct VariableLength { public int fixedSize; public fixed int varSize[1]; } Of course, this also means that you have to use stackalloc or other manual allocation to actually get a properly sized block of memory, computing said size yourself; but you also have to do it in C with malloc: byte* p = stackalloc byte[sizeof(VariableLength) + 10 * sizeof(int)]; var vl = (VariableLength*) p; Once you have a pointer, though, you can do vl->varSize[i] etc - this works because the type of vl->varSize when you access it is int*.
- oceanswave 9y ago
  Came here to say this — one of my first projects in the industry as an intern way back with .net 1.1 was to create an c# based application to parse through effectively binary serialized variable sized c structs.
  - int_19h 9y ago
    "fixed" was a C# 2.0 addition, though. Back in 1.x days, you basically had to declare that field as a simple scalar instead, and then use & to manually obtain the pointer (but then you could index it with [] etc, same as in C, so it doesn't really make that much of a difference in this case; "fixed" sure did come in handy for other stuff though).